Whiteboards, also known as dry erase boards, are commonly used in offices, schools, and other locations were a chalkboard might otherwise be found. Writings on a dry erase board are erasable by wiping lightly with felt, dry cloth or paper. Suitable whiteboard surfaces generally include a melamine, vinyl, polyethylene laminate, or enamel resin layer affixed to a backing. Such whiteboards are characterized in that they have hard, white surfaces that are very smooth in appearance, and are essentially nonporous. Alternatively, a whiteboard may comprise a sheet of polymeric film such as an acrylic or UV curable resin.
A variety of compositions are known for use in writing on impervious writing surfaces such as whiteboards. These coloring compositions suitable for use on whiteboards must erase easily without requiring a comprehensive cleaning. Additionally, the whiteboard compositions must be removable without leaving visible remains commonly termed "ghosting."
Whiteboard coloring compositions suffer from a variety of well known deficiencies. Most whiteboard markers are alcohol-based which may be toxic and, thus, are not appropriate for use by young children. For example, U.S. Pat. Nos. 4,954,174, 5,316,574, and 5,324,764 describe erasable ink compositions for writing on an impervious surface that contain an organic solvent such as an alcohol. Further, many whiteboard markers produce writings which are not readily erasable from whiteboards after the passage of a significant period of time. Finally, current whiteboard markers have a propensity to leave enduring stains on clothing. While permanence is a desirable characteristic of the so-called "permanent" markers, it is one of the most objectionable properties for coloring instruments used by young children.
Water-based marker compositions have been used. U.S. Pat. Nos. 5,412,021 and 5,561,175, for example, describe water-based compositions that contain a pigment, a separating agent, and a water-soluble resin. These aqueous compositions, however, lack fugitivity from fabrics and skin.
It is therefore one general object of the invention to provide a method of imparting skin fugitivity to a dry erase coloring composition.
Another object is to provide a dry erase coloring composition which, in addition to being washable from skin, exhibits enhanced launderability from fabrics.
A related object is to provide non-toxic, dry erase coloring compositions, such as inks, which are suitable for use by young children who may make marks on themselves and their clothing.
A further object of the invention is to provide a coloring composition suitable for use on whiteboards and other non-porous surfaces which is also washable from the skin and clothes.
These and other objects and advantages of the present invention, as well as additional inventive features, will be apparent to those skilled in the art from the following description of the invention and the appended claims.